Implantable head mounted neurostimulation system for head pain

ABSTRACT

An implantable head-mounted unibody peripheral neurostimulation system is provided for implantation in the head for the purpose of treating chronic head pain, including migraine. The system may include an implantable pulse generator (IPG) from which multiple stimulating leads may extend sufficient to allow for adequate stimulation over multple regions of the head, preferably including the frontal, parietal and occipital regions. A lead may include an extended body, along which may be disposed a plurality of surface metal electrodes, which may be sub-divided into a plurality of electrode arrays. A plurality of internal metal wires may run a portion of its length and connect the IPG&#39;s internal circuit to the surface metal electrodes. The IPG may include a rechargeable battery, an antenna, and an application specific integrated circuit. The IPG may be capable of functional connection with an external radiofrequency unit for purposes that may include recharging, diagnostic evaluation, and programming.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/717,912, filed on May 20, 2015, entitled IMPLANTABLE HEAD MOUNTEDNEUROSTIMULATION SYSTEM FOR HEAD PAIN (Atty. Dkt. No. SYNT60-32651),which published on Nov. 12, 2015 as U.S. Patent Application PublicationNo. 2015-0321004. U.S. application Ser. No. 14/717,912 is a Continuationof U.S. patent application Ser. No. 14/460,139, filed Aug. 14, 2014,published on Apr. 23, 2015 as U.S. Patent Application Publication No.2015-0112406, now U.S. Pat. No. 9,042,991, issued on May 26, 2015.Application No. 14/460,139 claims benefit of U.S. ProvisionalApplication No. 61/894,795, filed Oct. 23, 2013, entitled IMPLANTABLEHEAD MOUNTED NEUROSTIMULATION SYSTEM FOR HEAD PAIN (Atty. Dkt. No.SYNT-32185). U.S. patent application Ser. Nos. 14/717,912, 14/460,139and 61/894,795, U.S. Patent Application Publication Nos. 2015-0321004and 2015-0112406, and U.S. Pat. No. 9,042,991 are herein incorporated byreference in their entirety.

This application is related to U.S. patent application Ser. No.14/460,111, filed Aug. 14, 2014, published on Feb. 19, 2015 as U.S.Patent Application Publication No. 2015-0051678. U.S. patent applicationSer. No. 14/460,111 claims benefit of U.S. Provisional Application No.61/865,893, filed Aug. 14, 2013, the specifications of which are hereinincorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to a fully head mountedimplantable neurostimulation system and methods of treating migraineheadaches and other forms of chronic head pain.

BACKGROUND

Neurostimulation systems comprising implantable neurostimulation leadsare used to treat chronic pain. Conventional implantable peripheralneurostimulation leads are designed for placement in the spinal canal aspart of a spinal cord stimulation system, and for the therapeuticpurpose of treating various forms of chronic back and extremity pain.

SUMMARY

In various implementations, an implantable head-mounted, unibodyperipheral nerve stimulation system may be configured for implantationof substantially all electronics, including an on-site battery, at ornear the implanted electrodes on the skull. The system may include animplantable pulse generator (IPG) from which two neurostimulating leadsmay extend to a length sufficient to provide therapeuticneurostimulation unilaterally over the frontal, parietal and occipitalregions of the hemicranium. The system may be operable to providemedically acceptable therapeutic neurostimulation to multiple regions ofthe head, including the frontal, parietal and occipital regions of thehemicranium, substantially simultaneously.

Each of the leads may include an extended lead body; a plurality ofsurface metal electrodes disposed along the lead body, which may bedivided into two or more electrode arrays; and a plurality of internalelectrically conducting metal wires running along at least a portion ofthe length of the lead body and individually connecting an internalcircuit of the IPG to individual surface metal electrodes. The extendedlead body may comprise a medical grade plastic. The IPG may include arechargeable battery, an antenna coil, and an application specificintegrated circuit (ASIC). The IPG may be configured for functionallyconnecting with an external radiofrequency unit. The externalradiofrequency unit may be operable to perform various functionsincluding recharging the rechargeable battery, diagnostically evaluatingthe IPG, and programming the IPG.

Implementations may include one or more of the following features. TheIPG may be of proper aspect ratio with respect to the specific site ofintended implantation in the head, such as an area posterior to and/orsuperior to the ear. There may be an external portable programming unitthat is capable of achieving a radiofrequency couple to the implantedIPG. The IPG may have a rechargeable battery as a power source. Therechargeable battery may be inductively recharged through the skin.

Implementations may include one or more of the following features. Aneurostimulating lead may not include a central channel for a stylet. Aneurostimulating lead may have a smaller diameter than conventionalleads.

Implementations may include one or more of the following features. Thesystem may include the disposition of a sufficient plurality of surfaceelectrodes over a sufficient linear distance along the neurostimulatingleads to enable medically adequate therapeutic stimulation acrossmultiple regions of the head, including the frontal, parietal, andoccipital region of the hemicranium substantially simultaneously. Theextended array of surface electrodes may be divided into two or morediscrete terminal surface electrode arrays. The linear layout of themultiple surface electrode arrays may include at least one arraypositioned over the frontal region, at least one array positioned overthe parietal region, and at least one array positioned over theoccipital region.

Specific intra-array design features may include variations in thespecific number of electrodes allotted to each group; the shape of theelectrodes, e.g., whether the electrodes are cylindrical or flattened;the width of each electrode within each array, and the linear distanceintervals of separation of the electrodes within each array.

Various implementations may include a plurality of connection ports thatcan be connected with a plurality of leads and thus allow for attachingadditional leads.

In various implementations, methods of treating chronic pain may includemethods of treating chronic head and/or face pain of multipleetiologies, including migraine headaches; and other primary headaches,including cluster headaches, hemicrania continua headaches, tension typeheadaches, chronic daily headaches; further including secondaryheadaches, such as cervicogenic headaches and other secondarymusculoskeletal headaches.

In various implementations, methods of treating chronic pain may includemethods of treating head and/or face pain of multiple etiologies,including neuropathic head and/or face pain, nociceptive head and/orface pain, and/or sympathetic related head and/or face pain.

In various implementations, methods of treating chronic pain may includemethods of treating head and/or face pain of multiple etiologies,including greater occipital neuralgia, as well as the other variousoccipital neuralgias, supraorbital neuralgia, auriculo-temporalneuralgia, infraorbital neuralgia, and other trigeminal neuralgias, andother head and face neuralgias.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features,objects, and advantages of the implementations will be apparent from thedescription and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure and its features,reference is now made to the following description, taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 depicts a side view of a head-mounted, unibody neurostimulatorsystem for migraine and other head pain. The system features animplantable pulse generator (IPG) from which two neurostimulating leadsextend—a Fronto-Parietal Lead (FPL) and an Occipital Lead (OL). Eachlead includes a plurality of electrodes in a distribution and over alength to allow full unilateral coverage of the frontal, parietal, andoccipital portions of the head.

FIG. 2 depicts a side view of a Frontal Electrode Array (FEA) withInternal Wires. The FEA is disposed over the distal portion (such as8-10 cm) of the FPL, which anatomically places it over the frontalregion, and specifically over the supraorbital nerve and other adjacentnerves of the region. In general the layout, disposition and connectionsof the Internal Wires and Surface Electrodes disposed over the ParietalElectrode Array (PEA) and the Occipital Electrode Array (OEA) are thesame as that depicted for the FEA.

FIG. 3 depicts a side view of the Internal Wires exiting from the IPG'sInternal Circuit enroute to the Surface Electrodes disposed over the FPLand the OL.

FIG. 4 depicts a cross-sectional view of a Lead Central Body comprisinga Cylindrical Lead Body (with Internal Wires) between the IPG InternalCircuit and the Lead Surface Electrodes.

FIG. 5 depicts a rear view of a Head with a full Head-MountedNeurostimulator System In-Situ. Prominent here is the OL depictedpassing from the IPG caudally and medially across the occipital region,whereby the OEA is disposed in a fashion to cross over and cover themajor associated nerves—primarily the greater occipital nerve, buttypically including the lessor and/or third occipital nerve as well.Also depicted are the PEA and the FEA of the FPL as they cross and coverthe primary nerves of the Parietal Region, including theauriculo-temporal nerve, and the Frontal Region, including thesupraorbital nerve.

FIG. 6 depicts a side view of a Head with a full Head-MountedNeurostimulator System In-Situ. Prominent here is the PEA, as it coversa portion of the Parietal Region and the major associated nerves,including the auriculo-temporal nerve, as well as adjacent cutaneousnerves. Also depicted are the courses of the distal portion of the FPLand the OL, as they pass over and cover the associated nerves of theFrontal (Supraorbital) and Occipital Regions.

FIG. 7 depicts a front view of a Head with a full Head-MountedNeurostimualtor System In-Situ. Prominent here is the FEA, as it coversa portion of the Frontal (Supraorbital) Region and the major associatednerves—primarily the supraorbital nerve, but also commonly the greatertrochlear nerve, as well as adjacent nerves. Also depicted is the courseof the parietal portion of the FL.

INDEX OF ELEMENTS

10: Implantable Pulse Generator

11: Antenna

12: Battery

13: Application Specifc Integrated Circuit

14: Medical Plastic Cover

20: Fronto-Parietal Lead

20 a: Plastic Body Member

21 Distal End

22: Proximal End

22 a: Proximal Lead Segment

23: Distal Non-Stimulating Tip

24: Surface Metal Electrode

25: Frontal Electrode Array

26: Parietal Electrode Array

27: Inter-Array Interval

28 Point of Cross Section FIG. 4

29 Lead Internal Wire

30 Occipital Lead

31 Distal End

32 Proximal End

32 a Proximal Lead Segment

33 Distal Non-Stimulating Tip

34 Surface Metal Electrode

35 Occipital Electrode Array

36 Interelectrode Distance

37 Surface Electrode Width

38 Lead Internal Wire

39 Plastic Body Member

50 Occipital Region of Head

51 Greater Occipital Nerve

52 Lesser Occipital Nerve

53 Third Occipital Nerve

60 Parietal Region of Head

61 Auriculotemporal Nerve

70 Frontal Region of Head

71 Supraorbital Nerve

DETAILED DESCRIPTION

Referring now to the drawings, wherein like reference numbers are usedherein to designate like elements throughout, the various views andembodiments of implantable head mounted neurostimulation system for headpain are illustrated and described, and other possible embodiments aredescribed. The figures are not necessarily drawn to scale, and in someinstances the drawings have been exaggerated and/or simplified in placesfor illustrative purposes only. One of ordinary skill in the art willappreciate the many possible applications and variations based on thefollowing examples of possible embodiments.

A. Introduction

The present disclosure provides a fully head mounted implantableperipheral neurostimulation system designed for the treatment of chronichead pain. It incorporates multiple elements and features that take intoaccount the unique anatomic, physiologic, and other related challengesof treating head pain with implantable neurostimulation, thereby greatlyimproving on therapeutic response, patient safety, medical risk, andmedical costs, which combine to improve overall patient satisfaction.

Prior implantable peripheral neurostimulation systems and components,including leads and pulse generators, have been designed and developedspecifically as spinal cord stimulator systems and for the specifictherapeutic purpose of treating chronic back and extremity pain. Overthe years, these spinal cord stimulators were ultimately adopted andadapted for use as implantable peripheral nerve stimulators for thetreatment of migraine headaches, and other forms of chronic head pain;however, they were so utilized with full recognition of the inherentrisks and limitations given that they were developed only to address,and accommodate to, the unique anatomic and physiologic features of theback and chronic back pain.

U.S. Provisional Patent Application Ser. No 61/865,893 describes themanifold problems associated with the application of spinal cordstimulators for head pain as fundamentally due to design flawsassociated with, and inherent to, the use of an implantable therapeuticdevice in an area of the body that it was not designed for.

Indeed, the anatomy of the head, and the pathophysiology of headaches,and other forms of head pain, are so significantly different from theanatomy of the spinal canal, and pathophysiology of chronic back pain,that when spinal cord stimulators are utilized for cranial implants, theclinical problems associated with these differences manifest themselves.Importantly, these well-documented problems are clinically verysignificant and include issues of patient safety and satisfaction, therisk of an inadequate, or suboptimal, therapeutic response; and issueswith patient comfort and cosmetics; as well as a recognized increasedrisk of surgical complications and technical problems.

These medical issues stem from the design of conventional leads and theIPG. Conventional lead designs include a relatively large diameter, acylindrical shape, (often) inadequate length and the necessity ofimplanting the IPG in the torso and distant from the distal leads, and anumber and disposition of the surface electrodes and active lead arraysthat do not match the requirements. A cylindrical lead of relativelylarge diameter results in increased pressure on, and manifest tentingof, the overlying skin, particularly of the forehead. Becauseconventional leads are of inadequate length to extend from the head tothe IPG implant site, commonly in the lower back, abdomen, or glutealregion, lead extensions are often employed, and there are attendantrisks of infection, local discomfort, and cosmetic concerns.

With respect to prior leads: 1) There is only a single array ofelectrodes, with common lead options including 4, 8, or 16 electrodesdisposed over that single array; 2) The array is relatively short withmost leads having an array of from 5-12 cm in length; 3) Within thissingle array, the individual electrodes are disposed uniformly withconstant, equal inter-electrode distances. This results in the need toimplant multiple (often four or more) of the conventional leads toadequately cover the painful regions of the head.

There are several practical clinical outcomes that result from the useof prior leads for the treatment of chronic head pain. First, since theycomprise a single, relatively short active array, the currentlyavailable leads provide therapeutic stimulation to only a single regionof the head; that is, they can provide stimulation to only the frontalregion, or a portion of the parietal region, or a portion of theoccipital region. Therefore, if a patient has pain that extends overmultiple regions, then multiple separate lead implants arerequired—basically one lead implant is required for each unilateralregion. A great majority of patients with chronic headaches experienceholocephalic pain; that is they experience pain over the frontal andparietal and occipital regions bilaterally. Therefore, commonly thesepatients will need 4 to 7 leads implanted to achieve adequatetherapeutic results (2 or 3 leads on each side).

Second, the need for multiple leads includes considerable added expense,and more importantly, added medical risk associated with adverse eventsattendant to the multiple surgical procedures. Such adverse eventsinclude an increased risk of infection, bleeding, and technical issueswith the leads, e.g., lead fracture, lead migration, and localirritation.

Third, as the clinical database discloses, the inter-electrode spacingmay be of central therapeutic significance. That is, for example,whereas commonly pain over the occipital region is consistentlyeffectively treated by quadripolar leads (leads with four evenly spacedelectrodes) that have the electrodes relatively widely spaced apart(approximately a cm or more apart), clinically it is often found thatelectrodes configurations that are more narrowly spaced may be moreeffective over the supraorbital nerve and regions. Thus, a quadripolarlead that has the electrodes only 1-2 mm apart may be more effective inthis region, as it allows for more precise control of the deliveredelectrical pulse wave delivery.

Inter-electrode spacing is also of therapeutic significance. Forexample, whereas pain over the occipital region is commonly treatedeffectively by systems incorporating relatively widely-spacedquadripolar leads (four electrodes at approximately 1 cm or moreintervals), more narrowly spaced contacts are often more effective overthe supraorbital region.

When an IPG implant designed for spinal cord stimulation systems isemployed as a peripheral nerve stimulator for head pain, severaloutcomes result. First, the IPG is implanted at a considerable anatomicdistance for the cranial lead implants. Indeed, the leads must pass fromtheir distal cranial implant positions across the cervical region andupper back to the IPG implant location, which are most commonly in thelower back, lower abdomen, or gluteal region. The leads must crossmultiple anatomic motion segments, including the neck and upper backand/or chest at a minimum, and commonly include the mid back, lower backand waist segments, as well. The simple motions of normal daily lifeproduce adverse tension and torque forces on the leads across thesemotion segments, which in turn increases the risk of various outcomes,including lead migration and/or lead fracture. In addition, therelatively large size of a spinal cord stimulator IPG contributes tolocal discomfort, cosmetic concerns, and increased risk of infectionthat may become larger and harder to treat in proportion to the size ofthe IPG pocket.

The present disclosure is directed to an implantable head-mountedunibody peripheral neurostimulation system that includes an IPG fromwhich two neurostimulating leads extend to a length sufficient to allowfor therapeutic neurostimulation unilaterally over the frontal, parietaland occipital regions of the head.

The present disclosure addresses and effectively solves problemsattendant to publically available leads. The most important of these isthe fact that current leads can only adequately stimulate a singleregion of the head due to design element flaws associated with terminalsurface electrode number and disposition. The disclosure additionallyaddresses and solves other problems inherent with the currentlyavailable leads, including problems with cosmetics and patient comfort,particularly over the frontal regions, due the uncomfortable pressureplaced on the skin of the forehead, due the cylindrical shape andrelatively large diameter of the distal portion of the lead. Finally,the lead of the present disclosure solves the currently available leads'problem of inadequate lead length to reach a gluteal location of theimplantable pulse generator, which therefore necessitates the additionalrisk and expense of further surgery to implant lead extensions.

In one aspect, the implantable, head-mounted, neurostimulation systemfor head pain is operable for implantation in the head, and to provideneurostimulation therapy for chronic head pain, including chronic headpain caused by migraine and other headaches, as well as chronic headpain due other etiologies. The peripheral neurostimulator systemdisclosed herein takes into account unique anatomic features of thehuman head, as well as the unique, or singular, features of the variouspathologies that give rise to head pain, including migraine and otherheadaches, as well as other forms of chronic head pain. To date, allcommercially available systems that have been clinically utilized forimplantation as a peripheral neurostimulator system were actuallyoriginally designed specifically for placement in the epidural space, aspart of a spinal cord stimulation system, for the therapeutic purpose oftreating chronic back and/or extremity pain. Thus, there are currentlyno commercially available leads or fully system that have designs in thepublic domain, that have been designed and developed for use in the headand for head pain.

In another aspect, the implantable, head-mounted, neurostimulationsystem for head pain comprises multiple design features, includingdisposition of a sufficient plurality of surface electrodes over asufficient linear distance along the distal lead, such as will result inlead that, as a single lead, is capable of providing medically adequatetherapeutic stimulation over the entire hemicranium; that is, over thefrontal, parietal, and occipital region substantially simultaneously.Currently available systems, which were designed specifically forepidural placement for chronic back pain, are capable of only providingstimulation over a single region; that is over either the frontal regionalone, or the parietal region alone, or the occipital region alone.

In yet another aspect, the implantable, head-mounted, neurostimulationsystem for head pain comprises multiple design features, including thephysical grouping of the extended array of surface electrodes into threeor more discrete terminal surface electrode arrays. The linear layout ofthese two or more (preferably three or more) surface electrodes arraysis designed such that following implantation there would be at least onearray positioned over the frontal region, at least one array positionedover the parietal region, and at least one array positioned over theoccipital region. This feature further improves upon therapeuticeffectiveness of the extended terminal surface electrode arraysufficient for hemicranial stimulation by allowing for more precisecontrol of the therapeutic neurostimulation parameters.

In still another aspect, the implantable, head-mounted, neurostimulationsystem for head pain comprises multiple design features, includingincorporating individual design features within each of the three ormore individual surface electrode arrays; examples of such intra-arraydesign features would include the specific number of electrodes allottedto each group; whether the electrodes are cylindrical or flattened; thewidth of each electrode within each array, and the linear distanceintervals of separation of the electrodes within each array. Thisfeature further improves upon therapeutic effectiveness of the extendedterminal surface electrode array sufficient for hemicranial stimulation,and the grouping of these electrodes into three or more separate surfaceelectrode arrays, by providing each specific array location a uniqueintra-array design that takes into account, and thereby seeks tooptimizes, design elements that are known to be possibly or likelybeneficial to the therapeutic end result, given the anticipatedpost-implant anatomic location of that array.

In yet another aspect, the implantable, head-mounted, neurostimulationsystem for head pain comprises multiple novel design features, includingincorporating individual design features into a single lead design andthereby achieving additive benefits.

In still another aspect, an implantable, head-mounted, neurostimulationsystem for head pain results in a marked decrease in the number ofseparate lead implants required to adequately treat a single patient. Asingle implant will provide the same therapeutic anatomic coverage thatit would take the implantation of three or four of the currentlyavailable leads; that is instead of the current which often calls forthree or more leads to be implanted to provide adequate hemicranialcoverage, the same anatomic region may be covered with a singlestimulator lead implant. The lead provides extended coverage over thefull hemicranium; that is achieving medically acceptableneurostimulation unilaterally over the frontal, parietal, and occipitalregions simultaneously. In contrast, publically known leads are able toconsistently provide medically acceptable neurostimulation therapy onlyover a single region; meaning that it would require three separatesurgically placed lead implants to achieve the same therapeutic coverageof a single implant of a lead of the present disclosure. This willdecrease the total number of surgeries required, as well as the extentof each individual surgery, for many patients.

In another aspect, the present disclosure is directed to a system thatis fully localized to the head, which obviates the requirement ofcurrently available systems of having long leads and extensionsextending across the neck and back to IPG locations commonly in the lowback and gluteal region, and thereby decreases the risk of problemsattendant to such long leads and extensions, including discomfort,infection, technical extension issues such as fracture, and othermorbidities. This ultimately results in a decreased number of surgeriesrequired by a patient.

In other aspects the system may include one or more of the followingfeatures. A neurostimulating lead may not require a central channel fora stylet. A neurostimulating lead may have a smaller diameter thancurrently available leads.

In other aspects the system may include one or more of the followingfeatures. The system may include the disposition of a sufficientplurality of surface electrodes over a sufficient linear distance alongthe system's leads to enable medically adequate therapeutic stimulationacross multiple regions of the head, and preferably the entirehemicranium; that is, over the frontal, parietal, and occipital regionsimultaneously. The extended array of surface electrodes may be dividedinto two or more discrete terminal surface electrode arrays. Thepreferred linear layout of these multiple surface electrode arraysincludes at least one array positioned over the frontal region, at leastone array positioned over the parietal region, and at least one arraypositioned over the occipital region.

In other aspects intra-array design features may include variations inthe specific number of electrodes allotted to each group; the shape ofthe electrodes, e.g., whether the electrodes are cylindrical orflattened; the width of each electrode within each array, and the lineardistance intervals of separation of the electrodes within each array.

In other aspects, the system may a plurality of connection ports thatcan be connected with a plurality of leads and thus allow for attachingadditional leads should they later be required.

In another aspect, an implantable, head-mounted, neurostimulation systemfor head pain comprises multiple design features; including featuresaimed at improving patient safety by improving the incidence of adverseevents, including the risk of infection, as well as the risk andincidence of known technical problems associated with implanted leads,including lead migration and lead fracture, amongst others. The lead maycomprise two or more (i.e. three or more) surface electrode arrays, eachuniquely designed, that are disposed over a sufficient lead length toallow for medically acceptable therapeutic neurostimulator coverage ofat least regions within the supraorbital, parietal, and occipitalcranial regions. To achieve the same clinical coverage from a singleimplant, it would require three or more separately surgically implantedleads. Therefore, by reducing the number of surgical incisions, as wellas the number of surgically implanted leads, the associated risks ofadverse events are proportionally diminished.

In yet another aspect, an implantable, head-mounted, neurostimulationsystem for head pain may treat chronic head and/or face pain of multipleetiologies, including migraine headaches; and other primary headaches,including cluster headaches, hemicrania continua headaches, tension typeheadaches, chronic daily headaches, transformed migraine headaches;further including secondary headaches, such as cervicogenic headachesand other secondary musculoskeletal headaches; including neuropathichead and/or face pain, nociceptive head and/or face pain, and/orsympathetic related head and/or face pain; including greater occipitalneuralgia, as well as the other various occipital neuralgias,supraorbital neuralgia, auriculotemporal neuralgia, infraorbitalneuralgia, and other trigeminal neuralgias, and other head and faceneuralgias.

In other aspects, an implantable, head-mounted, neurostimulation systemfor head pain may not require a central channel for stylet placementover its distal (frontal) portions. The lead may improve patient comfortand cosmetics by virtue of its relatively small diameter over the distalportions of the lead, partially due the lack of a central styletchannel, as well as due to a progressive decrease in the number ofinternal wires continuing after each terminal electrode. The lead mayfurther improve cosmetic appearance and patient comfort by incorporatinga flattened lead design for that portion of the lead expected to be overthe frontal portion of the head.

Thus the present disclosure provides for a peripheral neurostimulationlead that is uniquely designed for implantation in the head as a therapyfor chronic head pain, and is designed to solve the known design issuesassociated with current leads, as the lead of the present disclosureseeks to optimize the therapeutic response, improve patient comfort,improve cosmetics, reduce the number of surgical leads required, reducemedical risk, and reduce medical costs.

B. Overview

Turning now to the drawings, which depict the system and several of itscomponents in various aspects and views, and in which similar referencenumerals denote similar elements. The drawings illustrate an IPG fromwhich two neurostimulating leads may extend to a length sufficient toallow for therapeutic neurostimulation unilaterally over the frontal,parietal and occipital regions. The leads include an extended plasticlead body; a plurality of surface metal electrodes disposed along thelead, which may be divided into two or more electrode arrays; aplurality of internal electrically conducting metal wires running alongat least a portion of its length and individually connecting the IPG'sinternal circuit to individual surface metal electrodes. The implantablepulse generator includes a rechargeable battery, an antenna coil, andASIC. The system may be operable to provide medically acceptabletherapeutic neurostimulation to multiple regions of the head, includingthe frontal, parietal and occipital regions simultaneously, and threefigures demonstrate various views of this feature as the lead isdepicted in-situ.

C. Full Head-Mounted Neurostimulator System

FIG. 1 depicts a side view of a full neurostimulator system, whichconsists of an implantable pulse generator (IPG) 10 along with twounibody plastic lead extensions—a Fronto-Parietal Lead (FPL) 20 and anOccipital Lead (OL) 30 of adequate length to extend to roughly themidline of the forehead and to the midline at the cervico-cranialjunction, respectively.

FIGS. 5, 6 and 7 depict posterior, lateral and frontal views of thesystem in-situ. The unit is demonstrated in an implant position wherethe IPG 10 is posterior and cephalad to the pinna of the ear. Thedrawings demonstrate the FPL 20 passing over the parietal 60 and frontal70 regions of the head, including auriculotemporal nerve 61 andsupraorbital nerve 71, in a manner that places the FEA over thesupraorbital nerve and the PEA over the auriculotemporal nerve. The OL30 is shown passing caudally and medially over the occipital region ofthe head 50 such that the OEA 35 cross over the greater occipital nerve51, the lesser occipital nerve 52, and the third occipital nerve 53.

D. Fronto Parietal Lead

Continuing with FIG. 1, the FPL as part of the unibody construction,extends from the IPG. The FPL comprises a plastic body member 20 a and aset of internal conducting wires 29.

The plastic body member 20 a is an elongated, cylindrical, flexiblemember, which may be formed of a medical grade plastic polymer. It has aproximal end 22, a distal end 21, and may be conceptually divided intofive segments along its linear dimension. Progressing from the proximalend 22, these segments sequentially include a proximal lead segment(PLS) 22 a, a parietal electrode array (PEA) 26, an inter-array interval27, a frontal electrode array (FEA) 25, and a distal non-stimulating tip23.

The lead internal wires 29 pass along the interior of the plastic bodymember as depicted in FIG. 4.

E. Frontal Electrode Array

Continuing with FIG. 1, the FEA 25 consists of a plurality of surfacemetal electrodes (SME) 24 uniformly disposed over a portion of thedistal aspect of the FPL 20. Lead internal wires 29 connect to the SME24 as depicted in FIG. 2, which represents the distal four SME 24 of thelead.

F. Parietal Electrode Array

Returning to FIG. 1, the PEA 26 consists of a plurality of SME 24uniformly disposed along a linear portion of the FPL. The PEA 26 isseparated along the FPL from the FEA by an inter-array interval 27. Itis separated only the lead from the IPG by the PLS 22 a. The leadinternal wires 29 connect to the individual SME 24 of the PEA in thesame fashion as the do with the SME of the FEA as shown in FIG. 2.

G. Occipital Lead

Continuing with FIG. 1, the occipital lead (OL) 30 as part of theunibody construction, extends from the IPG 10. It comprises a plasticbody member 39 and a set of lead internal wires 38 that pass through thecentral cylinder of the lead to connect to a series of SME 34, each ofsurface electrode width 37, that are uniformly disposed at aninterelectrode distance 36 from each other along a portion of the lengthof the lead. These lead internal wires 38 pass and connect in the samemanner as described above for the SME 24 of the FEA 25 as depicted inFIG. 2 and FIG. 4.

The plastic body member 39 is an elongated, cylindrical, flexiblemember, which may be formed of a medical grade plastic polymer. It has aproximal end 32 and a distal end 31. Progressing along the lead from theproximal end 32, these segments sequentially include a proximal leadsegment (PLS) 32 a, an occipital electrode array (OEA) 35, and a distalnon-stimulating tip 33.

H. Occipital Lead Array

As depicted in FIG. 1, the OEA 35 consists of a plurality of surfacemetal electrodes (SME) 34 uniformly disposed over a portion OL 30. Leadinternal wires 38 connect to the SME 24 in the same fashion as depictedfor the FEA as shown in FIG. 2.

I. Implantable Pulse Generator

Referring to FIG. 1 and FIG. 3, the three primary physical andfunctional components of the IPG 10 include a rechargeable battery 12,an antenna 11, and an application specific integrated circuit (ASIC) 13,along with the necessary internal wire connections amongst these relatedcomponents, as well as to the incoming lead internal wires 29, 39. Theseindividual components may be encased in a can made of a medical grademetal and plastic cover 24, which itself transitions over the exitingFPL 20 and OL 30.

K. Connections of Main Elements and Sub-Elements

The system may include a unibody construction to provide physical andfunctional continuity of the related components and sub-components.

The overall mechanistic purpose of an implantable neurostimulationsystem is to generate and conduct a prescribed electrical pulse wavefrom an IPG 10 down a set of lead internal wires 29, 38 running aportion of the length of the lead to specified programmed set of SME 24,34, whereby the current is then conducted by tissue and/or fluid to anadjacent, or nearby, set of one or more SME 24, 34, which in turn passesthe signal proximally down the lead wire 29, 38 back to the IPG 10 andits ASIC 13, thus completing the circuit.

L. First Embodiment

The first embodiment provides for a lead that incorporates one or moreof the features outlined above and includes a head-mounted, unibodyneurostimulating system comprising an IPG 10 and at least twoneurostimulating leads (FPL 20 and OL 30). The system may be implantedin a manner such that the IPG 10 and two leads 20, 30 are disposed asillustrated in FIG. 5, FIG. 6 and FIG. 7. The IPG 10 is capable offunctionally connecting to and communicating with a portable programmerand an external power source for battery recharging.

In this embodiment, the leads are constructed as described above and asdepicted in the drawings. The FPL 20 is approximately 26 cm in lengthfrom its proximal end 22 to its distal end 21. The FPL 20 has a distalnon-stimulating tip of approximately 3 mm in length that abuts the FEA,which may have ten SME 24 uniformly disposed over approximately 8 cm.This is followed by an inter-array interval 27 of approximately 4 cm,then the PEA, which may include eight SME 24 uniformly disposed overapproximately 6 cm, and finally a proximal lead segment 22 a that endsat the proximal end 22, where the lead transitions to the IPG 10 and thelead internal wires 29, 38 connect to the ASIC 13.

In this embodiment, the occipital lead may comprise a plastic bodymember 39 over which six SME 34 may be disposed uniformly overapproximately a 10 cm length of the lead, and the lead terminates inapproximately a 3 mm distal non-stimulating tip 33.

In this embodiment, the IPG 10 comprises the elements described aboveand depicted in the drawings, including an ASIC 13, a rechargeablebattery 12, and an antenna 11, which all may be housed in a medicalgrade metal can with plastic cover 14. In this embodiment the dimensionsof the IPG 10 measured along the outer surface of the plastic cover 14may be approximately 5 cm by 3 cm by 0.5 mm.

The system includes a portable programmer and a portable rechargingunit, both of which functionally couple to the IPG through aradiofrequency mechanism.

In this embodiment, the system is capable of handling a program from theportable programmer that includes such parameters as pulse amplitude,frequency and pulse width.

M. Alternate Embodiments

There are multiple alternate embodiments that preserve the features ofthe neurostimulation system disclosed herein, which include anexternally rechargeable and programmable IPG, sized and configured forimplantation in the head, and from which fronto-parietal and occipitalleads, along with their respect surface metal electrode arrays, extendto cover multiple regions of the head. In various embodiments, thespacing and dimensions of the electrode array(s) may be constant, or theelectrode arrays may be specifically designed with respect to electrodetype, dimensions, and layout for improving the therapeuticeffectiveness.

Thus, the disclosure comprises extended electrode array designs (two ormore regions by a single lead), and/or multiple arrays and optimizedintra-array electrode dispositions. The disclosure also comprises leadconfigurations, which include the capability of a modular lead designthat provides for ports on either the standard FPL and OLs. In anotherembodiment, the IPG receive additional separate leads, if and asnecessary either at the time of initial implant or in the future.

Further, the lead lengths, along with the specific technical makeup anddimensions of the individual surface metal electrodes and electrodearrays, may be varied to include more or less than three unilateralregions of the head (occipital, parietal, and frontal) contemplated bythe first embodiment. For example, a single IPG may energize and controlmultiple additional leads of varying lengths that ultimately could bedisposed over virtually every region of the head and face bilaterally.

At least two electrodes may be included per region, and while the firstembodiment calls for a total of 24 electrodes disposed over three arrayscovering three different regions of the head—the occipital, parietal andfrontal regions—there is no absolute limit to the maxim number ofelectrodes. Similarly, while the first embodiment calls for threeelectrode arrays, the disclosure contemplates two, or even one array (solong as the array covers at least two regions). There is also nolimiting maximum for the number of arrays. Also, there may be multiplevariations of design within each separate array, including for example,variations in the number, dimensions, shape, and metal composition ofthe individual electrodes, as well as the distance and constancy ofdistance between electrodes, within each array. Further, each array mayhave the same or completely different designs.

While the neurostimulation system has been described for implantation asa peripheral neurostimulator in the head and for head pain, it iscapable of being implanted and used as a peripheral nerve stimulatorover other regions of the head and face than described above and alsoover other peripheral nerves in the body.

N. Operation

When functioning; that is when the internal circuit of lead internalwires is connected to an IPG; the SME of the various arrays areprogrammed to function as anodes and cathodes. The generated electricalpulse wave then passes from the ASIC of the IPG to the associatedinternal lead wire, and ultimately to its associated terminal surfacemetal electrode. The current then passes a short distance from thesubcutaneous tissue to a contiguous, or nearby, electrode, whereby itpasses back up the lead to its associated proximal metal contact, andthen back to the IPG to complete the circuit. The generated pulse wavespass through the subcutaneous tissue between two terminal electrodesthat stimulates the sensory nerves of the area. When active, the IPG maybe programmed to produce continuous series of pulse waves of specifiedfrequency, amplitude, and pulse width. It is this series of pulse wavesactively stimulating a patient's locally associated nerves thatunderpins the therapeutic effect of the implanted unit. The electricalpulse wave then passes from a connected proximal surface metal contact,along the associated internal lead wire, and ultimately to itsassociated terminal surface metal contact.

It is to be understood that the implementations disclosed herein are notlimited to the particular systems or processes described which might, ofcourse, vary. It is also to be understood that the terminology usedherein is for the purpose of describing particular implementations only,and is not intended to be limiting. As used in this specification, thesingular forms “a”, “an” and “the” include plural referents unless thecontent clearly indicates otherwise. In addition, the term “coupling”includes direct and/or indirect coupling of members.

Although the present disclosure has been described in detail, it shouldbe understood that various changes, substitutions and alterations may bemade herein without departing from the spirit and scope of thedisclosure as defined by the appended claims. Moreover, the scope of thepresent application is not intended to be limited to the particularembodiments of the process, machine, manufacture, composition of matter,means, methods and steps described in the specification. As one ofordinary skill in the art will readily appreciate from the disclosure,processes, machines, manufacture, compositions of matter, means,methods, or steps, presently existing or later to be developed thatperform substantially the same function or achieve substantially thesame result as the corresponding embodiments described herein may beutilized according to the present disclosure. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

It will be appreciated by those skilled in the art having the benefit ofthis disclosure that this implantable head mounted neurostimulationsystem for head pain provides a unibody construction with implantedleads to cover the frontal, parietal, and occipital regions of the head.It should be understood that the drawings and detailed descriptionherein are to be regarded in an illustrative rather than a restrictivemanner, and are not intended to be limiting to the particular forms andexamples disclosed. On the contrary, included are any furthermodifications, changes, rearrangements, substitutions, alternatives,design choices, and embodiments apparent to those of ordinary skill inthe art, without departing from the spirit and scope hereof, as definedby the following claims. Thus, it is intended that the following claimsbe interpreted to embrace all such further modifications, changes,rearrangements, substitutions, alternatives, design choices, andembodiments.

1. A head-located neurostimulator, comprising: an implantable pulsegenerator (IPG), the IPG having: a first body including circuitry forgenerating stimulating signals and disposed in a first plane, a secondbody including a coil for inductively receiving power and disposed in asecond plane so that the first body is adjacent and non-overlapping thesecond body, when viewed from a side, the coil in the second body beinginterfaced with the circuitry in the first body, and a battery for beingcharged by the circuitry with inductive power received by the coil; afirst lead having a first lead body interfaced with the circuitry in thefirst body on a proximal end and having a first array of electrodesexposed to the exterior of the first lead body proximate a distal endthereof, each of the electrodes conductively and separately interfacedto the circuitry in the first body through the first lead body toreceive simulating signals therefrom; a second lead having a second leadbody interfaced with the circuitry in the first body on a proximal endand having a second array of electrodes exposed to the exterior of thesecond lead body proximate a distal end thereof, each of the electrodesconductively and separately interfaced to the circuitry in the firstbody through the second lead body to receive simulating signalstherefrom; and a coating disposed over the first and second bodies andat least a portion of the first and second leads on the proximal endsthereof to form a unibody construction; wherein the circuitry in thefirst body is operable to drive the electrodes in the first and secondarrays simultaneously, such that select ones of the electrodes can bedriven to provide stimulating signals.
 2. The head-locatedneurostimulator of claim 1, wherein the stimulating signals includepulsed signals.
 3. The head-located neurostimulator of claim 2, whereinthe stimulating signals pulse at predetermined frequencies.
 4. Thehead-located neurostimulator of claim 1, wherein the first and secondleads each include a plastic body member and a plurality of internalconducting wires.
 5. The head-located neurostimulator of claim 4,wherein each of the electrodes is conductively interfaced with one ofthe internal conducting wires.
 6. The head-located neurostimulator ofclaim 4, wherein the first and second leads are flexible.
 7. Thehead-located neurostimulator of claim 1, wherein the electrodes in thefirst array on the first lead are disposed uniformly along a linearportion of the lead at a first inter-electrode interval.
 8. Thehead-located neurostimulator of claim 7, wherein the electrodes in thesecond array on the second lead are disposed uniformly along a linearportion of the lead at a second inter-electrode interval.
 9. Thehead-located neurostimulator of claim 8, wherein the first lead has athird array of electrodes, each of the electrodes of the third arrayconductively interfaced to the circuitry in the first body to receivesimulating signals therefrom.
 10. The head-located neurostimulator ofclaim 9, wherein the third array of electrodes is disposed uniformlyalong a linear portion of the first lead at a third inter-electrodeinterval which is different than the first inter-electrode interval. 11.The head-located neurostimulator of claim 9, wherein the circuitry inthe first body is operable to drive the first, second, and third arrayssimultaneously.
 12. The head-located neurostimulator of claim 1, whereinthe circuitry disposed in the first body is operable to communicatewirelessly, via the coil, with a source external to the IPG.
 13. Thehead-located neurostimulator of claim 1, wherein at least one of theelectrodes is a cathode.
 14. The head-located neurostimulator of claim1, wherein at least one of the electrodes in each of the first andsecond arrays is an anode and another thereof is a cathode.
 15. Thehead-located neurostimulator of claim 2, wherein the stimulating signalspulse at predetermined pulse-widths.
 16. The head-locatedneurostimulator of claim 1, wherein the at least one of the electrodesis cylindrical in shape.
 17. The head-located neurostimulator of claim1, wherein at least one of the electrodes is flattened in shape.
 18. Ahead-located neurostimulator, comprising: an implantable pulse generator(IPG), the IPG having: a first body including circuitry for generatingstimulating signals and disposed in a first plane, a second bodyincluding a coil for inductively receiving power and disposed in asecond plane so that the first body is adjacent and non-overlapping thesecond body, when viewed from a side, the coil in the second body beinginterfaced with the circuitry in the first body, and a battery for beingcharged by the circuitry with inductive power received by the coil; afirst lead having a first lead body interfaced with the circuitry in thefirst body on a proximal end and having a first array of electrodesexposed to the exterior of the first lead body proximate a distal endthereof, each of the electrodes conductively and separately interfacedto the circuitry in the first body through the first lead body toreceive simulating signals therefrom; a second lead having a second leadbody interfaced with the circuitry in the first body on a proximal endand having a second array of electrodes exposed to the exterior of thesecond lead body proximate a distal end thereof, each of the electrodesconductively and separately interfaced to the circuitry in the firstbody through the second lead body to receive simulating signalstherefrom; and a coating disposed over the first and second bodies andat least a portion of the first and second leads on the proximal endsthereof to form a unibody construction; wherein the circuitry in thefirst body is operable to drive the first and second arrayssimultaneously, such that select ones of the electrodes can be driven toprovide stimulating signals; and wherein the electrodes in each of thefirst and second arrays are programmed to function as anodes andcathodes.